The evil eye refers to when one person harms another by means of the eye.
It was narrated that Jabir (RA) said: The Messenger of Allah (Peace and Blessing upon Him) said:
"The evil eye will put a man into his grave and a camel into the cooking pot." [Hilyat Al-Awliya' by Abu Na'im. Shaykh Al-Albani (may Allah have mercy on him) said: It is a Hasan Hadith - Al-Silsilah Al-Sahihah, 1250.]
Evil eye can follow a man until it makes him fall from a high mountain, and if it is able to overpower a healthy man it can kill him and put him in his grave, and if it overpowers a camel, it will fall and be injured, and its owner will slaughter it and cook it in a pot. So the evil eye is real and its effects are real. It may kill, or it may affect the spot or the things that the envier likes in the body of the person affected, or in himself or his possessions. This is the view of the scholars, such as Malik, Al-Shafi'i, Ahmad and others.
As for the symptoms of being affected by the evil eye, Shaykh ‘Abd al-‘Azeez al-Sadhaan (may Allaah preserve him) said:
If it is not a real sickness, then the symptoms may take the following forms:
Headaches that move from one part of the head to another; yellow pallor in the face; sweating and urinating a great deal; weak appetite; tingling, heat or cold in the limbs; palpitations in the heart; pain in the lower back and shoulders; sadness and anxiety; sleeplessness at night; strong reactions due to abnormal fears; a lot of burping, yawning and sighing; withdrawal and love of solitude; apathy and laziness; a tendency to sleep; health problems with no known medical cause.
These signs or some of them may be present according to the strength of the evil eye or the number of people who put the evil eye on others.
The difference between the evil eye and envy.
The Hasid (envier) is an envious man whose envy is accompanied by resentment, so he wishes that the blessing be taken away, whereas the 'A'in (the one who puts the evil eye on another) simply likes a thing. Hence the evil eye may come from a righteous man or woman, and a man may put the evil eye on his own wealth, child or family without realizing it. But the evil eye and envy have the same effect, which is causing harm to the thing that is liked or envied.
*good things good to share^^